I don't know of another way to connect the dots when you have multiple discrete (blue) pills all on the same Row/Column Shelf. Tableau can connect lines across one discrete pill, but will break lines because there are multiple panes being created when there are multiple pills.

The solution as I outlined should work, if you don't have a calculated field that can return a date at the appropriate level of detail, it is possible to create one. If you need assistance, I suggest posting a packaged workbook (.twbx) with some sample data.

I don't know of any way in Tableau to get the multiple bar graph overlaid with line charts like in your graph.

Tableau uses the structure of the underlying data to determine information to draw marks. That's different from a tool like Excel where we can "paint" pretty much anything we want anywhere we want on the view. The "rigidness" of Tableau gives a ton of flexibility for making views, but does impose some limits and I think you've run into one here.

The reason why Tableau is only drawing one line is because you have the single measure SUM(Revenue$) that is returning 4 marks, and then the marks are colored by DEVICE_OS. If you want more lines, it's possible to create a calculated field for each DEVICE_OS that is something like SUM(IF [DEVICE_OS] = "foo" THEN [Revenue$] END), then you can use Measure Values to draw multiple lines.

However, Tableau still won't connect the lines across the dates in this case. The basic issue is that you've got two discrete pills on columns. Tableau will compute a mark for each combination of those pills, and will connect marks to create a line within the pane created by the right-most pill (DEVICE_OS in your bottom pic), but will break marks between panes (the date/time). Like I said, I don't know of any way around that.